Aspinall Unit operations update: Gunnison Tunnel turning off, 600 cfs in Black Canyon

Fog-filled Black Canyon via the National Park Service
Fog-filled Black Canyon via the National Park Service

From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be decreased from 1500 cfs to 600 cfs on Tuesday, November 1st. This reduction will follow the shutdown of diversions to the Gunnison Tunnel. Release reductions will be coordinated with Gunnison Tunnel diversion reductions throughout the morning of November 1st. River flows downstream may fluctuate during the shutdown period but flows should steady out at the current level by the afternoon. The current content of Blue Mesa Reservoir is 610,000 acre-feet which is 73% full.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. Flows are expected to remain above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for November through December.

Currently, diversions into the Gunnison Tunnel are around 900 cfs and flows in the Gunnison River through the Black Canyon are around 600 cfs. After this release change Gunnison Tunnel diversions will be at zero and flows in the Gunnison River through the Black Canyon should still be around 600 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

@USBR: The next Aspinall Unit operations meeting is Thursday #ColoradoRiver #COriver

Aspinall Unit dams
Aspinall Unit dams

From email from Reclamation (Eric Knight):

The next Aspinall Operations meeting will be held this Thursday, August 18th at the Elk Creek Visitor Center at Blue Mesa Reservoir. Start time is 1 PM.

#ColoradoRiver: Aspinall Unit operations update #COriver — 1,000 cfs in Black Canyon

Sunrise Black Canyon via Bob Berwyn
Sunrise Black Canyon via Bob Berwyn

From email from Reclamation (Eric Knight):

Releases from Crystal Dam will be decreased from 2000 cfs to 1800 cfs on Wednesday, August 10th. July inflows to Blue Mesa Reservoir ended up being less than predicted and August inflow forecasts are also declining. The April-July runoff volume finished the season at 89% of average. The current content of Blue Mesa Reservoir is 757,000 acre-feet which is 91% full.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. Flows are expected to remain above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for August through December.

Currently, diversions into the Gunnison Tunnel are around 1000 cfs and flows in the Gunnison River through the Black Canyon are around 1000 cfs. After this release change Gunnison Tunnel diversions will still be at 1000 cfs and flows in the Gunnison River through the Black Canyon should be around 800 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

#ColoradoRiver: Aspinall Unit operations update #COriver

Aspinall Unit
Aspinall Unit

From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be increased from 1850 cfs to 2000 cfs on Friday, July 15th. Flows in the lower Gunnison River have been dropping quickly over the last week and are now just under the baseflow target. This increase is intended to raise flows in the lower Gunnison River as well as manage the reservoir content to reach the end of year winter target elevation. The current April-July runoff forecast is now at 91% of average. The current content of Blue Mesa Reservoir is 796,000 acre-feet which is 96% full.

Flows in the lower Gunnison River are currently below the baseflow target of 1500 cfs. This increase should restore flows to a level at or above the baseflow target.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1500 cfs for July.

Currently, diversions into the Gunnison Tunnel are around 1050 cfs and flows in the Gunnison River through the Black Canyon are around 850 cfs. After this release change Gunnison Tunnel diversions will still be at 1050 cfs and flows in the Gunnison River through the Black Canyon should be around 1000 cfs. Flows in the river may be less than 1000 cfs if the maximum capacity of the Crystal powerplant proves to be less than 2000 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

#ColoradoRiver: Reclamation Awards $17.8 Million Contract for Generator Rewinds and Excitation System Replacements for Wayne N. Aspinall Unit

Aspinall Unit dams
Aspinall Unit dams

Here’s the release from the US Bureau of Reclamation (Marlon Duke):

The Bureau of Reclamation awarded Toshiba America Energy Systems of Colorado a $17.8 million contract on Friday, June 10, 2016, to overhaul two generators, install new stator cores and frames, and improve oil and air cooling systems for its Wayne N. Aspinall Unit. Additional work will include new digital excitation systems for Blue Mesa, Morrow Point and Crystal power plants near Montrose, Colorado.

Work performed under this contract will replace update existing equipment to allow generation at full rated capacity and improve responsiveness to the dynamic demands of the electrical grid.

Each of the Unit’s power plants and dams are used to generate hydroelectric power and control water flow in the Gunnison River. The Wayne N. Aspinall Unit has a combined generating capacity of 291,000 kW.

Blue Mesa, Morrow Point and Crystal power plant and dams are part of Reclamation’s Wayne N. Aspinall Unit of the Colorado River Storage Project, which retains the waters of the Colorado River and its tributaries for agricultural and municipal use. The project furnishes the long-term regulatory storage needed to permit States in the upper basin to meet their flow obligation at Lees Ferry, Arizona, as defined in the Colorado River Compact and still use their apportioned water.

Aspinall Unit operations update: Black Canyon peak flow target 5,000+ cfs over 10 days

Sunrise Black Canyon via Bob Berwyn
Sunrise Black Canyon via Bob Berwyn

From email from Reclamation (Erik Knight):

The May 1st forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 525,000 acre-feet. This is 78% of the 30 year average. Based on the May 1st forecast, the Black Canyon Water Right and Aspinall Unit ROD peak flow targets are listed below:

Black Canyon Water Right

The peak flow target will be equal to 3,349 cfs for a duration of 24 hours.

The shoulder flow target will be 300 cfs, for the period between May 1 and July 25.

Aspinall Unit Operations ROD

The year type is currently classified as Average Dry

The peak flow target will be 8,070 cfs and the duration target at this flow will be 10 days.

Pursuant to the Aspinall Unit Operations ROD, releases from the Aspinall Unit will be made in an attempt to match the peak flow of the North Fork of the Gunnison River to maximize the potential of meeting the desired peak at the Whitewater gage, while simultaneously meeting the Black Canyon Water Right peak flow amount. The latest forecast for flows on the North Fork of the Gunnison River shows a peak of around 2,000 cfs occurring this weekend. This peak is followed by a couple days of lower flows and then higher flows are expected to return by the next weekend. If the forecast for flows on the North Fork of the Gunnison River continues to show a rise, the start of the ramp up towards the peak release may begin next week.

It is expected that the ramp up to the peak release will take 8 days. The current projection for spring peak operations shows flows in the Gunnison River through the Black Canyon in the 5,000 to 5,500 cfs range for 10 days in order to achieve the desired peak flow and duration at Whitewater. If actual flows on the North Fork of the Gunnison River are less than currently projected, flows through the Black Canyon could be even higher.

With this runoff forecast and corresponding downstream targets, Blue Mesa Reservoir is currently projected to fill to an elevation of around 7499.0 feet with an approximate peak content of 654,000 acre-feet.

Grand Junction: Aspinall Unit operations meeting, April 28 #ColoradoRiver #COriver

Aspinall Unit
Aspinall Unit

From email from Reclamation (Erik Knight):

The next Aspinall Operations meeting will be on Thursday, April 28th at 1PM.

Location is at the Western Colorado Area Office in Grand Junction at 445 West Gunnison Ave #221.

Topics of discussion will include:

  • summary of the snow season
  • discussion of runoff forecasts
  • projected spring operations
  • spring/summer weather outlook